2-Deoxy-D (3H) glucose (3H 2-DG) uptake was studied in isolated normal cerebral capillaries subjected to various gas mixtures during incubation. Under 100% N2 atmosphere, the specific 3H 2-DG capillary uptake was markedly decreased but could be recovered by substituting the N2 gas for oxygen or normal air. Free fatty acid serum albumin prevented the reduction of 3H 2-DG capillary uptake under anaerobic conditions, which could be abated by addition of individually tested saturated and unsaturated free fatty acids. This project is completed.